It seems clear, however, that, as between two countries of equal wealth, the probability of war varies with the disparity between their navies, and unless other nations are involved, is practically zero, when their navies are equal in power; and that, other factors being equal, the _greatest probability of war is between two countries, of which one is the more wealthy and the other the more powerful_.
In reckoning the probability of war, we must realize that _the most pregnant cause of war is the combination of conflicting interests with disparity in power_.

And we must also realize that it is not enough to consider the situation as it is now: that it is necessary to look at least ten years ahead, because it would take the United States that length of time to prepare a navy powerful enough to fight our possible foes with reasonable assurance of success.
Ten years, however, is not really far enough ahead to look, for the simple reason that, while we could get a great many ships ready in ten years, we could not get the entire navy ready as will be explained later.

If, for instance, some change in policies or in interests should make war with Great Britain probable within ten years, we could not possibly build a navy that could prevent our being beaten, and blockaded, and forced to pay an enormous indemnity.
Is there _no_ probability of this?
Perhaps there is no great probability; but there certainly is a possibility.

In fact, it might be a very wise act for Great Britain, seeing us gradually surpassing her, to go to war with us before it is too late, and crush us.

It has often been said that Great Britain could not afford to go to war with us, because so many of her commercial interests would suffer.